This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 10 |
| 3 | 48 |
| 4 | 176 |
| 5 | 560 |
| 6 | 1632 |
| 7 | 4480 |
| 8 | 11776 |
| 9 | 29952 |
| 10 | 74240 |
| 11 | 180224 |
| 12 | 430080 |
| 13 | 1011712 |
| 14 | 2351104 |
| 15 | 5406720 |
| 16 | 12320768 |
| 17 | 27852800 |
| 18 | 62521344 |
| 19 | 139460608 |
| 20 | 309329920 |
| 21 | 682622976 |
| 22 | 1499463680 |
| 23 | 3279945728 |
| 24 | 7147094016 |
| 25 | 15518924800 |
| 26 | 33587986432 |
| 27 | 72477573120 |
| 28 | 155960999936 |